Tip-induced superconductivity on the topological semimetals TaAs2 and NbAs2

Abstract

TaAs2 and NbAs2 are members of the MPn2 family with weak topological invariants of Z2 = [0;111]. Here, we report the tip-induced superconductivity achieved on both materials using the point-contact technique. Although the weak Z2 number leads to strongly crystal-orientation-dependent surface states, we observed a universal relationship between the zero-temperature upper critical field Hc2(0) and the critical temperature Tc for different crystal orientations. Combined with first-principles calculations, the findings here could identify a bulk band, instead of the much speculated surface bands, playing the dominant role in the induced superconductivity. These results predict a great possibility to realize superconductivity in other members of the MPn2 family possessing similar band structures and provide clues to understand the mechanism of tip-induced superconductivity.

Source-reported materials — not catalogue approval

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